347 Stroker swap with pics and specs | Page 3 | Ford Explorer Forums - Serious Explorations

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347 Stroker swap with pics and specs

Well I got some oil and filter. I bought valvoline 10w-30 and FL1A and did a change. Bad news is brewing in the bottom end I believe. As the oil poured out it had silver swirls all in it. My drain plug looked like it was stuck in mud with metal flake stuck to it. I cut the old filter open and it had metal slivers and some small chunks covering the filter. So I continued anyway. Afterwards all done I fired it up and let her warm up. After it got warm I had around 10-12 lbs oil pressure after running a good 10 min. So I thought ok maybe thin oil (which did not seem too thin or smell of gas when drained) and maybe that was my problem. I crawled under for one last leak check and heard a metal rubbing sound and also noticed oil dripping from dust shield between trans and engine. The engine also sounded like it was under load like something pulling on the engine. Also noticed smoke from valve cover breathers. I'm just not sure what the hell went wrong. Maybe I didn't break in properly on this one or TRE fouled up a bearing during the build. I feel I should I have built this one as I did all my others but I didn't have the time to run to machine shops. I built the 306 in my 93 stang, rebuilt the 03 cobra engine in my 97 cobra and built a 302 for my 73 maverick. None with problems. I'm feeling depressed. So Dono said it, the engine is coming out. Geezer I'm going to be a pro at explorer engine pulling!

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I had no knocking yet but just a lot more noise than the normal roller rocker roller lifter noise and it's very audible under the truck just laying under the oil pan. I guess I will find out when I pull it out and open the bottom up. I did get the three broke bolts out of the head on the old engine. So I have continued on the rebuild with new rings, bearings and gaskets. I will swap the engines until I figure out what the 347 needs. I want it in the truck because I bought a 351 block for a 408 stoker for the stang. I did think about putting the 351 in the explorer but it looked like I would fight with less space around the a/c.

Its **** like this that makes a guy want to burn the offending vehicle in the driveway and go buy something new.

Talking about frustrating.

So far I got the engines swapped. I just have to get the little stuff bolted and connected. What I have found without opening the bottom of my stroker is that half the oil pan bolts are missing and looking at the oil I drained from it has water in it unless my pan had some it (pretty sure it was dry). The noise I heard under the truck I believe was a trans cooler line that made its way on the idler pulley at the bottom right of the engine and rubbed. I did take the truck through some rough trails going hunting the Saturday after thanksgiving and i did beat on it pretty hard too. The pan bolts were a little short so they must have worked themselves loose and popped out. I will hopefully open the engine up by this weekend.

looks real nice

I finally got around to swapping the stock engine back in and had a little time to inspect the bottom end of the stroker. I must say the old engine runs like a new one. I found the thrust bearing is eat up really bad and ate up the thrust surface of the crank journal. All the main bearings are shot, but looks that the rest of the bearings are ok. The rest of the journals look ok as well. Not sure if it can be ground and polished by how bad its worn out. It will be a long time before I can get around to rebuilding the stroker thats why I put the stock 5.0 back in. Between trying to buy a house, my dad passing away, slow season at work and $10k pay cut. It's not going to be a fast recovery. I got a whopping 1,400+ miles out of the engine before failure. Oh well **** happens



Seeing this happen to multiple motors is kinda spooking me.

Turdle nailed it. you and i have something in common. i bought a truck from a member here on the forum that had a 347 in his truck for the drive train. knowing it had a rear main leak, and what sounded like a lifter tick, it ran fine. i had pulled some of the motor apart to do a cam change on it. long story short discovered that the crank was wiped out of it.



what was happening was the crank was walking around about a 1/4 inch do it it eating the thrust bearing, and eating into the crank. it to is a scat crank, but a cast, not forged. however, this motor has about 40,000 kms (about 25,000 miles). both myself, and the member i bought it from dont know when the damage started. the oil didnt look like yours either.
pull some rod caps off!!!!!
all of the bearings on the rod ends on mine were worn on one side.
also, my thrust bearing is worn on the same side. you may also want to look at the crank were the rods are and make sure they too didnt wear into the crank. with all the damage that mine had, even if is was a forged crank, i woudnt have had it repaired. it would have been too far gone.
what does your converter look like? does it looked like it ballooned? see if there are crank bolt imprints on it. i am still trying to figure out what cause the crank in mine to do what it did. im hoping that it isnt a problem that scat doesnt know about.....
keep posting as you find things. this now has my full attention because i was going to send my motor into the machine shop in the next 2 weeks, but may delay it now that i have seen this.


I was thinking about the torque converter ballooning. I didn't see any bolt impressions on the converter, but I didn't intentionally look for them. I did try to move the crank fore and aft this morning and couldn't get any movement but there's not a lot of room to get to anything to pry on the balancer or converter. As for the crank I believe I was originally wrong on the crank being forged. I found my original invoice and the part number is a cast scat crank. I was talking to an engine builder who has seen this in cases on cheap cranks (not saying scat makes cheap junk) where the thrust and/or journal surfaces are not ground even and/or not smooth. I didn't build this engine so I didn't get the chance to see and inspect anything during assembly. I did check the rod bearings and they are worn already but the crank journals look smooth.

I'm thinking now from day one I did a half hour break in and brought it to operating temp several times. Then changed the oil and noticed metal in oil but thought just normal for brake in. I put around 75 miles very easy driving and changed oil again and notice metal again. I then changed around 500 miles and noticed metal again. I still haven't run it hard by this time. I think I had problems from day one. I didn't have any problems with a 306 I put together about 6 years ago.

I'm not thinking the converter ballooned to cause my problems or could have been ballooned before the swap. I come down with the flu so as soon as I feel better I will pull the dust shield and remove the converter bolts and check if I have play between the flexplate and converter.

Another thing I was thinking about last night was, what are you running for your trans and converter? Are they both stock? Now the reason why I also ask this is the member I bought the truck from had told me that when he first put his together, the trans burnt the o/d band out, and had to put the stock trans and converter back in so he could drive it while the damaged trans was being repaired. I can't say yours did this but I am thinking maybe that when he had the stock trans and converter in that's when the damage happen because there are no signs of my converted being ballooned (bolt marks) but I haven't measured the diameter of it yet either

It's the stock converter and trans with original 278,000+ miles. I did think about maybe hydro pressure under load from the converter pushing forward or maybe the pump gears pushing the converter. However I think thrust bearings are meant to withstand quite a bit of load even at high RPM. For example my 97 cobra I put an 03 engine with a kbelle 2.3 with a center force clutch. The clutch had a lot more pedal pressure than the stock one. I have no idea what the pressure would be on the flywheel. The 306 I put together had a manual trans.

If i get a weekend where I can pull the trans to check the converter size I may try that soon. The only thing that sucks with that are the bolts to the engine are a nightmare to get. I guess the best way I found is to pull the upper intake and get them from up top. I just hope I don't tear the stock engine up if I do have a ballooned converter.

From what I have found is that converters don't actually change size (from what I found). The internals are what balloon and push on the crank. The marks that would be left on the converter from the crank bolts would be from the flexplate flexing. I also thought maybe my new 28oz flexplate has less clearance. I talked to a local engine builder and he thinks I wasn't making enough power to balloon the TC. Maybe I'm wrong and the converter is ballooned from the engine and ballooning does change the physical size. I also had a 95 cougar that I ran a 3000 stall and 100 hp wet nos system and ran that until I threw a rod at 234,000+ miles. That trans was rebuilt twice each time about 100k apart


that is very interesting. but i am not sure that would be your problem. it would have destroyed the 302 you have back in it now.
also, the guy that does all my trans work (have known him personally for 20+ years, and is a walking book of knowledge) had told me when a converter balloons, it will make it change shape, and stay that way

Your trans guy could be right. I've been talking to an engine builder that I don't personally know. I'm hoping it's not my converter because I would hate to pull the trans for another converter and possibly have to rebuild both engines. This weekend if I get time I'll do some more checking on the flexplate to convert clearances and see if there is any play with converter bolted. I'm worried about destroying my stock engine after what you have informed me of. I do believe it could be the converter but don't want to.

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i would have to think one of the easiest ways to find out in your situation would be to unbolt the converter and see if it slides back or not or if you have any play in it while its unbolted. if it does, i would have to think its something else. if it doesnt, then panic.....